This Phase II application is for support of a project to develop a contraceptive spermicidal gel that has enhanced antimicrobial properties. During Phase I the investigator 1) developed a gel base of carbopol that resisted hydrogen peroxide degradation, thereby maintaining physical stability, 2) demonstrated that a gel configuration containing 1% H2O2 maintained sufficient peroxide for acceptable shelf life, 3) demonstrated that the gel preparation did not effect condom integrity, 4) demonstrated that the gel H2O2 was completely released within two hours of application, 5) demonstrated that H2O2 gels have higher buffering capacity, 6) showed that at the concentrations used in his new contraceptive gel system, lactobacillus are not annihilated to the degree that other organisms are destroyed. In order to make the commercial gel that is this project's primary aim, the applicant plans to investigate the effectiveness of several (80) contraceptive gel formulations. These will be evaluated for physical-chemical qualities, in vitro anti-microbial activity, spermicidal activity, antiviral activity, and antilactobicillus activity. A single formulation will then be chosen for in vitro (FDA Phase I) testing after separation into it components (gel, gel + nonoxynol, gel+ H2O2 and gel+N-9+H2O2) . Finally, this formulation will be tested in vivo for spermicidal activity. The applicant believes that successful completion of these activities will provide a product that will be of interest to a large pharmaceutical company for further evaluation and eventual commercialization. PROPOSED COMMERCIAL APPLICATION: Commercial application will be as a vaginal contraceptive intended to reduce the risk of acquiring a sexually transmitted infection at the time of sexual intercourse. It may be sold over the counter and may have wide application in geographical location where sexually transmitted infection are a significant health threat. The vehicle could also be used to deliver other anti-infective in which the base compound synergizes the effect of other anti-microbials.